Multisource configuration for ALSA

[Latebo Querty]

Hi

I would like to get some help, because I have difficulties to make a good
configuration for my alsa installation.

I'm having a Raspberry pi 3 and a HifiBerry AMP2 soundcard.

I could set up the basic asound.conf to have everything working, but I have
difficulties to set up a more complex example.

I would like to ask for your help to try to fix it.

I have set up the latest version of Raspbian Lite version.
I have installed shairport-sync.

Technical infos about the setup

======================================================
uname -a
Linux Konyha 4.19.97-v7+ #1294
https://support.hifiberry.com/hc/requests/1294 SMP Thu Jan 30 13:15:58
GMT 2020 armv7l GNU/Linux ======================================================
aplay -lL
null
Discard all samples (playback) or generate zero samples (capture)
default
sysdefault:CARD=sndrpihifiberry
snd_rpi_hifiberry_dacplus, HiFiBerry DAC+ HiFi pcm512x-hifi-0
Default Audio Device
dmix:CARD=sndrpihifiberry,DEV=0
snd_rpi_hifiberry_dacplus, HiFiBerry DAC+ HiFi pcm512x-hifi-0
Direct sample mixing device
dsnoop:CARD=sndrpihifiberry,DEV=0
snd_rpi_hifiberry_dacplus, HiFiBerry DAC+ HiFi pcm512x-hifi-0
Direct sample snooping device
hw:CARD=sndrpihifiberry,DEV=0
snd_rpi_hifiberry_dacplus, HiFiBerry DAC+ HiFi pcm512x-hifi-0
Direct hardware device without any conversions
plughw:CARD=sndrpihifiberry,DEV=0
snd_rpi_hifiberry_dacplus, HiFiBerry DAC+ HiFi pcm512x-hifi-0
Hardware device with all software conversions
* List of PLAYBACK Hardware Devices *
card 0: sndrpihifiberry [snd_rpi_hifiberry_dacplus], device 0: HiFiBerry
DAC+ HiFi pcm512x-hifi-0 [HiFiBerry DAC+ HiFi pcm512x-hifi-0]
Subdevices: 1/1
Subdevice #0 https://support.hifiberry.com/hc/requests/0 : subdevice #0
https://support.hifiberry.com/hc/requests/0 ======================================================
cat /etc/asound.conf
pcm.!default {
type hw card 0
}
ctl.!default {
type hw card 0
}
=====================================================
sudo -u shairport-sync id
uid=999(shairport-sync) gid=995(shairport-sync)
groups=995(shairport-sync),29(audio)
======================================================
tail /boot/config.txt
[pi4]
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]

dtoverlay=hifiberry-dacplus
dtoverlay=i2s-mmap
======================================================

Result: shairport is running well, sound is OK.

Great, i want to achive 2 more goals:

• have an equalizer to fine tune bass and treble

• set up a dmix with alsa, to be able to run 2 application sources.
  Namely:

• shairport-sync: https://github.com/mikebrady/shairport-sync

• scream: https://github.com/duncanthrax/scream

New asound.conf

cat /etc/asound.conf
pcm.hifiberry {
type hw card 0
}

pcm.!default {
type plug
slave.pcm "dmixer"
}

pcm.dmixer {
type dmix
ipc_key 1024
slave {
pcm "hifiberry"
channels 2
}
}

ctl.dmixer {
type hw
card 0
}
======================================================
sudo service shairport-sync restart
======================================================

Result: shairport is running well, but there is NO sound :(

Scream is not running and there is no other application using the sound
device.

Please help me to fix it.

Thanks